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Diet and Rheumatoid Arthritis in Women: A Possible Protective Effect of Fish Consumption

Shapiro, Jean A.^1,2; Koepsell, Thomas D.^1,3; Voigt, Lynda F.²; Dugowson, Carin E.^1,4; Kestin, Mark^1,2; Nelson, Lee J.²

Author Information

¹From the Departments of Epidemiology and ³Health Services, School of Public Health and Community Medicine, and ⁴Division of Rheumatology, Department of Medicine, University of Washington, and the ²Fred Hutchinson Cancer Research Center, Seattle, WA.

Address reprint requests to: Jean A. Shapiro, Fred Hutchinson Cancer Research Center, 1124 Columbia Street, MP 381, Seattle, WA 98104–2092.

Supported by Contract N01-HD-62914 from the National Institute of Child Health and Human Development.

Submitted April 11, 1995; final version accepted October 5, 1995.

Epidemiology 7(3):p 256-263, May 1996.

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Abstract

Some researchers have hypothesized that omega-3 fatty acids, found primarily in fish oils, may protect against the development of rheumatoid arthritis. We conducted a population-based case-control study in women, comparing 324 incident rheumatoid arthritis cases with 1,245 controls. We used a food frequency questionnaire to ascertain diet during a 1-year period 5 years before a reference date (first physician visit for joint symptoms). Consumption of broiled or baked fish, but not of other types of fish, was associated with a decreased risk of rheumatoid arthritis. The adjusted odds ratios (OR) for 1-<2 servings and ≥2 servings of broiled or baked fish per week, compared with <1 serving, were 0.78 [95% confidence interval (CI) = 0.53–1.14] and 0.57 (95% CI = 0.35–0.93). Other analyses showed associations with protein as a percentage of calories (adjusted OR for the top quartile as compared with the bottom quartile = 0.65; 95% CI = 0.46–0.94) and total calories (adjusted OR for the top quartile = 1.62; 95% CI = 1.15–2.28). The associations with broiled or baked fish, protein, and calories became stronger when we restricted our analysis to cases positive for rheumatoid factor. These results support the hypothesis that omega-3 fatty acids may help prevent rheumatoid arthritis.